Recording device



S. A. BOKOVOY ET AL Nov. `1, 1938.

RECORDING DEVICE Filed Aug. 29, 1936 NNY ` .and QSSQA l v nventorGiraud/QM (Ittorneg Patented Nov. 1, 1938 UNITED STATES i RECORDINGDEVICE Samuel A. Bokovoy, Ventnor, and Paul D. Gerber, Woodlynne, N. J.,assignors to Radio Corporation of'Americ'a., a corporation of DelawareApplication August 29, 1936, Serial No. 98,622

, 4 Claims.

Our invention relates to recording devices. More particularly it relatesto a recording device in which a plurality of operations are recorded atsubstantially the same time by a single printer operating on a singlesheet of recording paper.

We are aware that numerous recording instruments are in use. In mostcases these recorders indicate the operation of a single device. In someinstances a plurality of separably operated instruments record theoperation of a plurality of devices on a single strip of paper. Ourinvention is to be distinguished from recorders of the prior art by thefact that a single printing device is arranged with a plurality of camopll erated elements whereby the operation of a multiplicity of devicesmay be recorded on a series of separate tracks by a single printer. Ourinstrument, which will be more fully described in connection with theaccompanying drawing which 2o shows a schematic yembodiment of ourinvention, may be used to simultaneously record a plurality ci radiofacsimile transmissions.

One of the objects of our invention is to provide means for recordingthe operation ofa plu- 25 rality of devices.

Another object is to provide means for sep\ arately indicating theoperation of a plurality of devices on a single recordingr sheet bymeansof a single recording device.

so A further object is to simultaneously operate a rotating helicalmember and a plurality of cam operated switches whereby the helicalmember is in effect divided into a plurality of operating portionscorresponding to a plurality of recording 35 tracks.

A still further object is to provide means for simultaneously recording,on a single recordenel plurality of separate radio facsimiletransmissions.

40 In the accompanying figure, a roll of recording paper I and a roll ofcarbon or transfer paper 3 are mounted on a suitable support 5. Springsor other suitable retarding means may be used to frictionally engage therolls to prevent the 45 paper from unwinding too rapidly. The carbonside of the sheet of roll 3 is placed next to the recording paper andthe two papers are fed through thefeed rolls l, 9. The feed roll may beknurled or suitably coated with rubber'to prom vide a positive means foruniformly feeding the two sheets of paper across the printing cylinderII. The printing cylinder carries a single, raised, helical element I3.This helix is preferably a uniform spiral arranged so that ka singleturn is 5 Just completed around the circumference and (oi. 2x4-1.5)

substantially within the length of the printing cylinder II.

The shaft carrying the printing cylinder is extended to carry aplurality of cams I5. Each of the cams respectively operates one of theswitches Il whose circuit connections will be described below. The camsare arranged to engage the switch so that theon contact portion of eachswitch corresponds with a denite portion or angular position of thehelical element I3. The

several switches I 1 are preferably arranged so` that their contacts arecompleted in succession. The printing cylinderv and cams are rotated bymeans of a motor I 9,' which may include reducing gears. The motor ispreferably energized by an alternating current of constant frequency. Ifsuch power supply is available, we prefer to use a synchronous motorwhich is especially suitable for facsimile reproduction. This motor alsodrives a pulley 2i which is coupled by a reversed belt 23, or the like,to a pulley 25 which is in turn connected to the feed roll l.

A printer motor 2l is suitably supported by brackets, which are notshown, so that therprinter bar 29 onv each` downward stroke engages thecarbon paper which in turn presses on the recording paper and helicalmember i3, at the.

point of intersection of I3 with the plane of the bar. The power fordriving the printer motor is preferably derived through the followingcircuit connections:

Each oi the switches Il, which may have their common terminals engagedby the cams, are connected to a lead 3 i. This lead is connected to theinput circuit of an audio frequency generator represented by 33.. Thisgenerator may be a thermionic oscillator, electromagnetic machine, orthe like. The other input terminal to the generator is connected to thecommon lead of a plurality of devices 35 whose operations are to berecorded. The other terminal of the devices under test are eachrespectively connected to the remaining terminals of the cam operated Byway of example, the devices under test may be the make and break contactof a thermostat, the make and break contacts of a bank of elevators orany plurality of devices which either have in themselves an electricallyoperated circuit or which may be arranged to include an off and onswitch. vThe output of the audio frequency generator is connected to asuitable amplifier 31 Whose power supply is represented by referencenumeral 39. The output of the amplifier is connected to the printermotor 21.

Having described the essential elements of our invention, we shall nowdescribe its mode of operation. It will be assumed that the power supplycircuit of motor I9 has been completed and that the motor is driving thefeed rolls and the cylinder carrying the helical'member at a suitablerate of speed. While the speed ofl these members isI not critical, weprefer to operatethe feed rolls at a small fraction of the speed of therecording cylinder. This may be accomplished by properly selecting thereduction gea-rs contained within motor i9. One of the gears may be usedto suitably reduce the speed of the cylinder II and the other to affecta much greater reduction between the motor and pulley 2l. Alternately,or in addition, the ratio of the diameters of pulleys 2| and 25 may beselected to provide `suitable speed reduction for the feed rolls. Itwill be seen that the contacts of the several switches I1 aresuccessively closed and opened by the operation of the cams I5. If thedevice under test is in operation and if its connected cam switch is inthe on contact position, thecompletion ofthe circuit through or by thedevice under test will energize or complete the circuit of the audiofrequency generator. The output of the generator will then be amplied bythe amplifier 31. The amplified output operates the printer motor .21 tothereby drive the printer bar 29 up and down along the axis of theprinter I I. On each downward stroke the printer bar will press thepapers against the helical member I3 at the point at which the helicalmember intersects the plane of the printer bar. This will cause thecarbon paper to leave an impression, or dot, on the recording paper atthat point, provided the device under test is in operation. If the`device under test is not in operation, the audio frequency currents arenot fed to the amplifier and the printer motor 21 does not operate. Therecording paper nevertheless continues to traverse the recordingcylinder. Since the device under test can only operate when the camoperated switch is closed it will be apparent that the printer motor canonly leave the record on that portion of the helical member whichcorresponds to the closing of the cam switch.

The shape and size of each dot or impression made by the down-stroke ofthe printer bar is determined by the nature of the area of contact atthe point of intersection of the lower surface of the printer bar andthe surface of helical member I 3. Helical member I3 may have a roundedsurface, and since it intersects the plane of the printer bar at anappreciable angle the point of contact is quite small and may appear asa single dot. Since the motion of the printing cylinder II and the paperI is small with respect to the frequency of vibration of the printerbar, adjacent points or dots may overlap and merge into a substantiallyuniform area. The angle that the transverse edge of this area makes withthe edge of the paper depends on how far the paper travels during eachrevolution of helical member I3. Since for reasons of paper economy thepaper travel-is preferably very slow, the areas recorded appear to besubstantially rectangular.-

By offsetting the cams as shown the entire helical member can be dividedinto separately operating portions corresponding to the separate devicesunder test. If, for example, the devices under test are thermostaticallycontrolled ovens the printed record will not only show relative periodswhen the ovens are being heated but it will also show whether any of thethermostatically operated elements are erratic in their operation.

inasmuch as the paper may be fed at a. uniform rate which, by way ofexample, may be one inch per minute, it is not necessary to print a timeinterval scale. However, if exact time intervals are desired a timingdevice such as a clock operated switch 38 may be substituted for one ofthe devices under test. Thisclock operated switch will leave a uniformseries of marks and spaces corresponding to the record 4I on therecording paper. It is -obvious that these intervals may be equivalentto one or two minutes or any other suitable time scale. The operation ofthe other devices may be compared to'the time scale if time intervalsare the essence of the test in question. In many cases, we have foundthat the exact timing is not of prime importance but merelyirregularities of operation are of interest. In the drawing, the tracks43 parallel to the edges of the recording sheet. are each a record ofirregular operation. T'he track, 45, remote from the standard track,indicates regular operation.

'I'hus we have described a. simple recording mechanism in which a singleprinting motor and a single recording sheet are used to simultaneouslyindicate the operation of a plurality of devices. It should beunderstood that while we do not limit our devicesto any particulararyrangementwe have found that the audio irequency generator may beoperated at a frequency of 1000 \cycles. By using a frequency of thisorder the amplifier construction is very much simplified. It should alsobe understood that the plurality of cam operated switches permit the useof a single generator, amplifier and printer motor. If the generatorcanl be operated at a high current level and controlled by the deviceunder test, the amplifier is not essential. It should also be understoodthat instead of operating the printer 'motor by an alternating currentit may be operated by direct current. We have found that the preferredform oi' alternating current operation prevents sticking of the printermotor. Instead of using carbon paper for recording it is within the'skill of those familiar with this art to'substitute an ink recordingmeans. For ext ample, an inked ribbon such as is used on a typewritermay be substituted for the roll of carbon paper, as shownin Fig. 6 of U.S. Patent No. 2,046,328.1ssued July 7, 1936,'to E. E. Kleinschmidt etal.

We claim as' our invention:

1. A recording systemcomprising a helical member, means for rotatingsaid helical member, means for feeding a recording sheet across saidhelical member, ay printer motor, a printer bar, means coupling saidprinter bar and printer motor, means for energizing said printer motorto thereby move said bar toward said helical member, and means includinga. plurality of cam operated-devices for dividing said recording into aseries of separate tracks substantially parallel to the sides of saidsheet.

2. A recording system comprising a helical member, means for rotatingsaid helical member, means for feeding a recording sheet across saidhelical member, a printer motor, a printer bar, a connection betweensaid printer bar and said printer motor, means for energizing said motorwhereby said bar is moved in the direction which will cause said sheetto engage said helirality of cams operated in synchronism with saidhelical member, a plurality of switches operated by said cams andcircuit connections for limiting the operation of said printer motor tointervals corresponding` with the contacting periods of said switches.

3. A device for indicating the operation of a plurality of devicesincluding in combination a helical member, a plurality of cam operatedswitches having oil? and on contacts, a plurality of cams for operatingsaid switches, means for rotating said helical member and said cams.means for feeding a recording sheet over said helical member, and amovable printer bar and marking means' for recording on said recordingsheet the operation of said plurality of devices in accordance with theon contact of said switches.

4. A device of the character described including in combination ahelical member, a plurality of cam operated switches having oi and oncontacts, cams having switch operating positions differentially spacedabout the axis of the helical member for operating said switches, meansfor rotating said helical member and said cams, means for feeding arecording sheet overv said helical member, a plurality of devices whoseoperation is to be recorded, means connecting each of said devices withdifferent switches of said plurality, and va movable printer bar andmarking means for recording on said recording sheet the operation ofsaid plurality of devices in accordance with the on contact of saidswitches.

SAMUEL A. BOKOVOY.

PAUL D. GERBER.

